Interesting shot i like the way the snake is way over to the left and leaves all that amazing colour as a backdrop.The comment about the tongue being blurred is right because it is a shame as it ruins it just slightly but you could clone it out on photoshop if you wanted.

Most snake shots you see with frozen tounges have been shot with flash with close to zero background light. The flash esstentially freezes the motion. Probably close to impossible to get the lit background and a frozen tounge unless the ambient light was allowing for faster than 1/2000th exposures.